Stackable valve system

ABSTRACT

A blow molding machine having the valves integrated into the valve block is disclosed. The valve pistons form annular rings stacked vertically along the stretch rod axis. The valve pistons activate by moving up/down along the stretch rod axis. The valve seat for each vertically stacked valve is formed radially around the stretch rod.

RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 12/444,536 filed on Apr. 6, 2009 entitled “A Ring Shaped ValvePiston and Its Use in a Blow Moulding Machine” which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to the field of blow molding, and inparticular, to a ring shaped valve piston around the stretch rod/blownozzle hole of a blow molding machine

2. Background of the Invention

Blow molding uses low and high pressure air to expand a pre-form part ina mold cavity. Typically the blow molding process uses 4 valves, a highpressure valve, a low pressure valve and two exhaust valves. The highand low pressure valves are known as the blow valves because thesevalves supply the air used to “blow” the pre-form into its final shape.The valves are typically connected to a valve block and the valve blockfeeds the blow nozzle that forms a seal against the pre-form/bottleinlet. The space between the outlets on the blow valves and thepre-form/bottle inlet is known as dead space. The dead space is filled,first with low pressure air, and then with high pressure air, for eachblow mold cycle. The low and high pressure air must also be vented fromthe dead space during each blow molding cycle.

Older blow molding machines connected the blow valves to the valve blockusing low and high pressure lines. The pressure lines and thepassageways in the valve block created large dead spaces, causing slowcycle times. Some newer blow molding machines attached the blow valvesand exhaust valves directly to the valve block, eliminating the pressurelines between the valves and the valve block and thereby reducing thedead space. An example of a blow molding machine that attaches the blowvalves and exhaust valves directly to the valve block is disclosed inU.S. Pat. No. 6,905,326 to Voth et al. entitled “Blow molding machinecomprising control valves, which are mounted on the blowing device andwhich control the blowing air” which is hereby incorporated byreference. These newer blow molding machines still have dead spaceformed along the entire length of the passageways formed in the valveblock (also called a valve carrier) that connect the blow valves to theblow nozzle.

SUMMARY OF THE INVENTION

A blow molding machine having the valves integrated into the valve blockis disclosed. The valve pistons form annular rings stacked verticallyalong the stretch rod/blow nozzle axis. The valve pistons activate bymoving up/down along the stretch rod/blow nozzle axis. The sealingsurface for each vertically stacked valve is formed around the stretchrod/blow nozzle.

ASPECTS

One aspect of the invention includes, a blow molding machine having avalve block with a stretch rod/blow nozzle extending through a hole inthe valve block, characterized by:

a cylindrical bore formed in the valve block where the cylindrical axisof the cylindrical bore is parallel with the stretch rod/blow nozzle andconcentric with the hole in the valve block and where the cylindricalbore has a bottom surface;

a valve piston having a generally circular shape with a central holewhere the valve piston is located in the cylindrical bore of the valveblock with the stretch rod/blow nozzle passing through the central hole;

a sealing surface located on the valve piston where the sealing surfacecompletely surrounds the stretch rod/blow nozzle, the valve pistonconfigured to move between an open position and a closed position bymoving along an axis formed by the stretch rod/blow nozzle;

the sealing surface configured to form a seal that surrounds the stretchrod/blow nozzle when the valve piston is in the closed position therebypreventing radial fluid flow into or away from the stretch rod/blownozzle.

Preferably, the sealing surface is on a bottom side of the valve pistonand forms a seal against the bottom surface of the cylindrical bore.

Preferably, the sealing surface forms a seal against a control chamberring installed into the cylindrical bore of the valve block.

Preferably, the sealing surface forms a seal against a top surface ofthe control chamber ring.

Preferably, the sealing surface is adjacent to the central hole of thevalve piston.

Preferably, the sealing surface has a shape selected from the followinggroup: circular, oval, square, rectangular, rounded rectangle,octagonal.

Preferably, an operating chamber ring located in the cylindrical borewhere the operating chamber ring is a generally flat circular shape withan inner hole where the outer diameter of the operating chamber ring isconfigured to seal against the inner diameter of the cylindrical bore;

a plurality of tabs extending downwards from a bottom side of theoperating chamber ring forming a plurality of gaps spaced around thebottom surface of the operating chamber ring where the plurality of tabsrest on the bottom surface of the cylindrical bore;

a circular groove formed in the wall of the cylindrical chamber andlocated at the bottom edge of the cylindrical chamber such that fluid inthe circular groove can flow into the plurality of gaps spaced aroundthe bottom surface of the operating chamber ring.

Preferably, a control chamber ring located in the cylindrical bore wherethe control chamber ring has a flat ring shaped top with a firstcylindrical section extending downward from an outer diameter of theflat ring shaped top and a second cylindrical section extending downwardfrom an inner diameter of the flat ring shaped top and where a pluralityof slots are formed in the bottom of the first cylindrical section andwhere the outer diameter of the control chamber ring is configured toseal against the inner diameter of the cylindrical bore;

the valve piston is sealed between the first cylindrical section and thesecond cylindrical section forming a control chamber in a top part ofthe control chamber ring with a plurality of holes passing through thefirst cylindrical section near the flat ring shaped top into the controlchamber.

Another aspect of the invention comprises a plurality of stackablevalves where each valve is characterized by:

an operating chamber ring having a flat ring shaped body with aplurality of tabs where the plurality of tabs are spaced around theouter perimeter of the flat ring shaped body and extend downward from abottom side of the flat ring shaped body;

a control chamber ring stacked on top of the operating chamber ringwhere the control chamber ring has a flat ring shaped top with a firstcylindrical section extending downward from an outer diameter of theflat ring shaped top and a second cylindrical section extending downwardfrom an inner diameter of the flat ring shaped top and where a bottom ofthe first cylindrical section rest on a top side of the operatingchamber ring and where a plurality of slots are formed in the bottom ofthe first cylindrical section;

a valve piston captured between the operating chamber ring and thecontrol chamber ring where the valve piston has a generally flat diskshaped top with a third cylindrical section extending downwards at aninner diameter of the generally flat disk shaped top and where a bottomsurface of the third cylindrical section forms a sealing surface, thevalve piston configured to move between an open position and a closedposition by moving along the cylindrical axis of the third cylindricalsection.

Preferably, a first one of the plurality of stackable valves is stackedon top of a second one of the plurality of stackable valves and wherethe sealing surface of the valve piston in the first one of theplurality of stackable valves seals against a top surface of the controlchamber ring in the second one of the plurality of stackable valves.

Preferably, a first one of the plurality of stackable valves is stackedon top of a second one of the plurality of stackable valves and wherethe plurality of tabs on the operating chamber ring in the first one ofthe plurality of stackable valves rest against a top surface of thecontrol chamber ring in the second one of the plurality of stackablevalves creating a plurality of gaps that allow radial fluid flow betweenthe operating chamber ring in the first one of the plurality ofstackable valves and the top surface of the control chamber ring in thesecond one of the plurality of stackable valves.

Preferably, a first one of the plurality of stackable valves is stackedon top of a second one of the plurality of stackable valves and where abottom surface of the first cylindrical section of the control chamberring in the first one of the plurality of stackable valves is spacedabove a top surface of the control chamber ring in the second one of theplurality of stackable valves creating a gap of height h that allowradial fluid flow between the bottom surface of the first cylindricalsection of the control chamber ring in the first one of the plurality ofstackable valves and the top surface of the control chamber ring in thesecond one of the plurality of stackable valves.

Preferably, the plurality of stackable valves is located inside acylindrical bore in a valve block.

Preferably, the plurality of stackable valves are stacked and flanged toeach other.

Another aspect of the invention comprises a method of operating a blowmolding machine having a first fluid passageway formed along a length ofa stretch rod/blow nozzle, characterized by:

supplying fluid, during a first blow molding step, to the first fluidpassageway through a first ring shaped passageway that surrounds thefirst fluid passageway;

sealing the first ring shaped passageway, during a second blow moldingstep, with a sealing member that surrounds the first fluid passageway.

Preferably, the method further comprises venting the fluid, during athird blow molding step, from the first fluid passageway through asecond ring shaped passageway that surrounds the first fluid passageway.

Another aspect of the invention comprises a method of assembling a blowmolding machine, characterized by:

(a) inserting an operating chamber ring into a cylindrical chamberformed in a valve block;

(b) inserting a valve piston into the cylindrical chamber;

(c) inserting a control chamber ring into the cylindrical chamberthereby capturing the valve piston between the operating chamber ringand the control chamber ring;

repeating steps (a)-(c) at least one more time.

Preferably, the method further comprises forming a seal between a wallof the cylindrical chamber and an outer diameter of the operatingchamber ring when the operating chamber ring is inserted into thecylindrical chamber;

forming a seal between the wall of the cylindrical chamber and an outerdiameter of the control chamber ring when the control chamber ring isinserted into the cylindrical chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional isometric view of valve block assembly 100in an example embodiment of the invention.

FIG. 2 a is an isometric top view of an operating chamber ring 108 in anexample embodiment of the invention.

FIG. 2 b is an isometric bottom view of an operating chamber ring 108 inan example embodiment of the invention.

FIG. 3 a is an isometric top view of a control chamber ring 106 in anexample embodiment of the invention.

FIG. 3 b is an isometric bottom view of a control chamber ring 106 in anexample embodiment of the invention.

FIG. 4 a is an isometric top view of a valve piston 110 in an exampleembodiment of the invention.

FIG. 4 b is an isometric bottom view of a valve piston 110 in an exampleembodiment of the invention.

FIG. 5 is detail A from FIG. 1 in an example embodiment of theinvention.

FIG. 6 is detail B from FIG. 1 in an example embodiment of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1-6 and the following description depict specific examples toteach those skilled in the art how to make and use the best mode of theinvention. For the purpose of teaching inventive principles, someconventional aspects have been simplified or omitted. Those skilled inthe art will appreciate variations from these examples that fall withinthe scope of the invention. Those skilled in the art will appreciatethat the features described below can be combined in various ways toform multiple variations of the invention. As a result, the invention isnot limited to the specific examples described below, but only by theclaims and their equivalents.

FIG. 1 is a cross sectional isometric view of valve block assembly 100in an example embodiment of the invention. Valve block assembly 100comprises valve block 102, stretch rod/blow nozzle 104, four controlchamber rings 106 a-106 d, four operating chamber rings 108 a-108 d,four valve pistons 110 a-110 d and four pilot valves 112. Valve block102 has a central cylindrical chamber 101. The stretch rod/blow nozzle104 extends vertically through the center of the central chamber 101 andout through a hole in the bottom of the central cylindrical chamber 101.Four sets of valves are vertically stacked in the central cylindricalchamber 101 around the stretch rod/blow nozzle 104. Each valve comprisesa control chamber ring, an operating chamber ring and a valve piston.The bottom or lowest valve comprises operating chamber ring 108 dsitting against the bottom surface of the central cylindrical chamber101 in valve block 102, control chamber ring 106 d sitting on top ofoperating chamber ring 108 d and valve piston 110 d captured between thecontrol chamber ring 106 d and the operating chamber ring 108 d. Valveblock 102 also has a number of inlet and outlet ports (114, 116 and 118)for feeding low pressure, high pressure, and exhaust air to and from thedifferent valves. The two upper valves in valve bock assembly 100 areshown in the open position and the two lower valves are shown in theclosed position. In one example embodiment of the invention, the orderof the valves from top to bottom is P1, AR, P2, exhaust, but in otherexample embodiments the order of the valve may be different.

FIG. 2 a is an isometric top view of an operating chamber ring 108 in anexample embodiment of the invention. FIG. 2 b is an isometric bottomview of an operating chamber ring 108 in an example embodiment of theinvention. Operating chamber ring 108 is a generally circular parthaving a generally flat ring shaped body with a plurality of tabs 230extending down from the generally flat ring shaped body. An O-ring orgasket groove 232 is formed in the outer edge of the generally flat ringshaped body. The inner diameter 234 of the generally flat ring shapedbody forms a sealing surface for the valve piston (not shown). Inoperation, the operating chamber ring 108 is stacked against the bottomsurface of the central cylindrical chamber 101 formed in the valve block102, or against the top of a control chamber ring 106. An O-ring orgasket 580 installed in the O-ring or gasket groove 232 seals againstthe cylindrical walls of the central cylindrical chamber 101 formed inthe valve block 102. The plurality of tabs 230 hold the generally flatring shaped body above the bottom of the central chamber or above thetop of a control chamber, forming a plurality of gaps 236. The pluralityof gaps 236 allow radial air flow from the valve block, towards thestretch rod/blow nozzle 103, underneath the generally flat ring shapedbody.

FIG. 3 a is an isometric top view of a control chamber ring 106 in anexample embodiment of the invention. FIG. 3 b is an isometric bottomview of a control chamber ring 106 in an example embodiment of theinvention. Control chamber ring 106 has a generally flat disk shapedbody with a central hole. An inner hollow cylindrical section 346extends downward from the inner edge of central hole of the generallyflat disk shaped body and an outer cylindrical section 344 extendsdownward from the outer edge of the generally flat disk shaped body. TwoO-ring or gasket grooves 342 are formed in the outer diameter of theouter cylindrical section 344. A plurality of holes 343 are also formedin the outer cylindrical section 344. In one example embodiment of theinvention the holes are formed between the two O-ring or gasket grooves342 on the outer diameter of the outer cylindrical section 344. Theholes angle upward and exit near the top of the inner diameter of theouter cylindrical section 344. The inner surface of the outercylindrical section 344 and the outer surface of the inner hollowcylindrical section 346 form sealing surfaces for the valve piston 110.A plurality of channels or gaps 450 are formed in the bottom of theouter cylindrical section 344. In operation, a control chamber ring 106is inserted into the central chamber formed in the valve block 102, andstacked on top of an operating chamber ring 108, capturing a valvepiston 110 in-between the operating chamber ring 108 and the controlchamber ring 106. O-rings or gaskets installed in the O-ring or gasketgrooves 342 form seals between the control chamber ring 106 and thecylindrical walls of the central cylindrical chamber 101 formed in thevalve block 102.

FIG. 4 a is an isometric top view of a valve piston 110 in an exampleembodiment of the invention. FIG. 4 b is an isometric bottom view of avalve piston 110 in an example embodiment of the invention. Valve piston106 is a generally circular part with a flat disk shaped top section 461with a central hole and a generally cylindrical section 462 extendingdownward from the inner diameter of the hole in the center of the diskshaped top section 461. The outer edge of the disk shaped top section461 has a groove 460 configured to hold a first seal. The outer diameterof the generally cylindrical section 464 has a groove 460 configured tohold a second seal. The bottom surface 466 of the generally cylindricalsection 464 forms a valve surface and seals against the bottom surfaceof the central cylindrical chamber formed in the valve block 102, oragainst the top of a control chamber ring 106. The inner diameter of thegenerally cylindrical section 464 has a first and second groove (468 and470) configured to hold a third and fourth seal (not shown). A pluralityof breath holes 472 for the O-rings or gaskets are formed radiallythrough the top segment of the generally cylindrical section 464. Inoperation, valve piston travels vertically along an axis concentric withthe cylindrical axis of the generally cylindrical section 464. The firstseal in groove 460 forms a seal with the inner diameter of the outercylindrical section 344 of the control chamber ring 106. The second sealin groove 464 form a seal with the inner surface 234 of an operatingchamber ring 108. The third and fourth seals in grooves 468 and 470 formseals against the outer diameter of the inner hollow cylindrical section346 of the control chamber ring 106.

FIG. 5 is detail A from FIG. 1 in an example embodiment of theinvention. FIG. 5 shows one side of the lowest valve comprisingoperating chamber ring 108 d sitting against the bottom surface of thecentral cylindrical chamber 101 in valve block 102, control chamber ring106 d sitting on top of operating chamber ring 108 d and valve piston110 d captured between the control chamber ring 106 d and the operatingchamber ring 108 d. O-rings or gaskets 580 form seals between theoperating chamber ring 108 d and the valve block 102 and between thecontrol chamber ring 106 d and the valve block 102. Valve piston 110 dis shown in the closed position with valve seat 466 sealed against thebottom surface of the central cylindrical chamber 101 formed in valveblock 102. Valve seat 466 may also be called a sealing surface 466, avalve surface 466, or the like. Distance d1 between the top of valvepiston 110 d and the bottom of control chamber ring 106 d is the maximumtravel for valve piston 110 d. The bottom of the inner hollowcylindrical section 346 of control chamber ring 106 d does not contactthe bottom surface of the central cylindrical chamber 101 in valve block102, but forms a circular gap of height h that surrounds the stretchrod/blow nozzle 104. A passageway with width g is formed between thestretch rod/blow nozzle 104 and the valve block 102 and allows air totravel down the stretch rod/blow nozzle 104 and into the pre-form. Thevalve surface 466 is width w away from the entrance to the passagewayrunning down the stretch rod/blow nozzle 104. The dead space is acylindrical space having height h, radius R1 and thickness w.

Pilot air is fed through circular groove 591 formed in the cylindricalwall of central cylindrical section 101 and through holes 343 intocontrol chamber 593, forcing valve piston down into the closed position.In one example embodiment of the invention the lowest valve is anexhaust or air recycle valve. Valve surface 466, sealed against thebottom of central cylindrical chamber, prevents air from flowing fromthe blown bottle (not shown) into exhaust chamber 590. When the valve isopened (not shown) air flows from the bottle, along the stretch rod/blownozzle 104 passageway, underneath the valve surface 466 into exhaustchamber 590, between the gaps 236 formed between the tabs 230 on thebottom side of operating chamber ring 108 d, and into circular groove588. Air is vented through circular groove 588 formed in the cylindricalwall of the central cylindrical chamber 101 through a connection (notshown) to one of the outlet ports formed in valve block 102. Seals 586installed in the second and third grooves formed in the valve piston 110d form seals between the valve piston and the control chamber ring 106 dand the operating chamber ring 108 d.

FIG. 6 is detail B from FIG. 1 in an example embodiment of theinvention. FIG. 6 shows one side of the top valve in valve assembly 100comprising operating chamber ring 108 a sitting against the top surfaceof the control chamber ring 106 b, control chamber ring 106 a sitting ontop of operating chamber ring 108 a and valve piston 110 a capturedbetween the control chamber ring 106 a and the operating chamber ring108 a. O-rings or gaskets 580 form seals between the operating chamberring 108 a and the valve block 102 and between the control chamber ring106 a and valve block 102. Valve piston 110 a is shown in the openposition with valve seat 466 above the top of control chamber ring 106 bby distance d2. Valve piston 110 a may have some clearance (distance d3)between the top of valve piston 110 a and the bottom of control chamberring 106 a. The bottom of the inner hollow cylindrical section 346 ofcontrol chamber ring 106 a does not contact the top surface of controlchamber ring 106 b, but forms a circular gap of height h that surroundsthe stretch rod/blow nozzle 104. A passageway with width g is formedbetween the stretch rod/blow nozzle 104 and the inner diameter of thecontrol chamber rings and allows air to travel down the stretch rod/blownozzle 104 and into the pre-form.

Pilot air is exhausted from control chamber 693 through holes 343 andinto circular groove 691 formed in the cylindrical wall of centralcylindrical section 101, allowing valve piston 110 a to be forced intothe open position by low pressure air in chambers 688 and 690. In oneexample embodiment of the invention the top valve is a P1 valve. The gapbetween valve surface 466 and the top of control chamber ring 106 ballows air to flow from circular groove 688, between the gaps 236 formedbetween the tabs 230 on the bottom side of operating chamber ring 108 ainto chamber 690, underneath the valve surface 466 and along stretchrod/blow nozzle 104 passageway and into the pre-form (not shown). Thelow pressure air is supplied through circular groove 688 formed in thecylindrical wall of the central cylindrical chamber 101 through aconnection (not shown) to one of the inlet ports formed in valve block102. Seals 686 installed in the second and third grooves formed in thevalve piston 110 a form seals between the valve piston and the controlchamber ring 106 a and the operating chamber ring 108 a.

The example embodiments disclosed above show the active valve surfacesor sealing surfaces (surface 466) forming circular rings around thestretch rod/blow nozzle. Other shapes are possible in other exampleembodiments, for example square, rectangular, rounded rectangle,octagonal, oval, and the like. The example embodiments disclosed aboveshow the sealing surfaces on the bottom side of the valve piston. Inother embodiments the sealing surface may be on the top side of thevalve pistons or the sealing surface may be around the periphery of thepiston. The example embodiments disclosed above show the stackablevalves installed into a cylindrical bore inside a valve block. In otherexample embodiments the control chamber ring and operating chamber ringmay be configured to be clamped or fastened together such that a valveblock is not needed.

1. A plurality of stackable valves where each valve is characterized by:an operating chamber ring (108) having a flat ring shaped body with aplurality of tabs (230) where the plurality of tabs (230) are spacedaround the outer perimeter of the flat ring shaped body and extenddownward from a bottom side of the flat ring shaped body; a controlchamber ring (106) stacked on top of the operating chamber ring (108)where the control chamber ring (106) has a flat ring shaped top with afirst cylindrical section (344) extending downward from an outerdiameter of the flat ring shaped top and a second cylindrical section(346) extending downward from an inner diameter of the flat ring shapedtop and where a bottom of the first cylindrical section (344) rest on atop side of the operating chamber ring (108) and where a plurality ofslots (450) are formed in the bottom of the first cylindrical section(344); a valve piston (110) captured between the operating chamber ring(108) and the control chamber ring (106) where the valve piston (110)has a generally flat disk shaped top with a third cylindrical sectionextending downwards at an inner diameter of the generally flat diskshaped top and where a bottom surface (466) of the third cylindricalsection forms a sealing surface (466), the valve piston (110) configuredto move between an open position and a closed position by moving alongthe cylindrical axis of the third cylindrical section.
 2. The pluralityof stackable valves of claim 1 where a first one of the plurality ofstackable valves is stacked on top of a second one of the plurality ofstackable valves and where the sealing surface (466) of the valve piston(110) in the first one of the plurality of stackable valves sealsagainst a top surface of the control chamber ring (106) in the secondone of the plurality of stackable valves.
 3. The plurality of stackablevalves of claim 1 where a first one of the plurality of stackable valvesis stacked on top of a second one of the plurality of stackable valvesand where the plurality of tabs (230) on the operating chamber ring(108) in the first one of the plurality of stackable valves rest againsta top surface of the control chamber ring (106) in the second one of theplurality of stackable valves creating a plurality of gaps (236) thatallow radial fluid flow between the operating chamber ring (108) in thefirst one of the plurality of stackable valves and the top surface ofthe control chamber ring (106) in the second one of the plurality ofstackable valves.
 4. The plurality of stackable valves of claim 1 wherea first one of the plurality of stackable valves is stacked on top of asecond one of the plurality of stackable valves and where a bottomsurface of the first cylindrical section (344) of the control chamberring (106) in the first one of the plurality of stackable valves isspaced above a top surface of the control chamber ring (106) in thesecond one of the plurality of stackable valves creating a gap of heighth that allow radial fluid flow between the bottom surface of the firstcylindrical section (344) of the control chamber ring (106) in the firstone of the plurality of stackable valves and the top surface of thecontrol chamber ring (106) in the second one of the plurality ofstackable valves.
 5. The plurality of stackable valves of claim 1 wherethe plurality of stackable valves is located inside a cylindrical bore(101) in a valve block (102).
 6. The plurality of stackable valves ofclaim 1 where the plurality of stackable valves are stacked and flangedto each other.
 7. A method of assembling a blow molding machine,characterized by: (a) inserting an operating chamber ring into acylindrical chamber formed in a valve block; (b) inserting a valvepiston into the cylindrical chamber; (c) inserting a control chamberring into the cylindrical chamber thereby capturing the valve pistonbetween the operating chamber ring and the control chamber ring;repeating steps (a)-(c) at least one more time.
 8. The method ofassembling a blow molding machine of claim 7, further characterized by:forming a seal between a wall of the cylindrical chamber and an outerdiameter of the operating chamber ring when the operating chamber ringis inserted into the cylindrical chamber; forming a seal between thewall of the cylindrical chamber and an outer diameter of the controlchamber ring when the control chamber ring is inserted into thecylindrical chamber.